Does one scene affect other scenes?
Each scene in a blender file is separated from each other, using it's own settings.

The data in a blend file can however be shared between scenes, this may be an object, mesh data, material etc. For example when you selecting a material, every material in the file will be listed and show up the same in every scene. When you use the same data block in multiple scenes then changing the item in one scene will also change it in other scenes.

The easiest way to tell if an item is unique is by the name, data blocks linked between scenes will have identical names. Here you can see that Suzanne is the same object linked between scenes, while Suzanne.001 is a different object that is only in scene.003. 



If you want to use the same object in multiple scenes select it and press CtrlL and under Objects to Scene choose which scene you wish to link it to.



So the answer to your question will depend on how your file is setup, this should help you find out and to setup your file as you want.